Roadblocks for tornado-safe homes

"It is simply not practical to make the whole house safe in case of tornado," he said, and that's mainly because doors and windows would need to be protected against debris impact.

The best that can be done is to improve what he calls the "connections."

The way a house is built now, roof trusses, joists and rafters are set atop the walls and nailed down. These don't have much resistance to uplift, and the mode of failure in a tornado is typically that the roof lifts off and the walls have no lateral stability so the whole house collapses. If the garage door blows off, internal pressure intensifies, so the house really doesn't have a chance.

Kiesling suggests strengthening the connections where the wall attaches to the floor and roof, and also along the ridgelines of the roof.

Other than that, the best option, he advocates, is to design a safe room in the house, which can be done at initial construction or through retrofit at a cost of about $4,000 to $5,000.

Basements are also an option, but only if the basement has a concrete roof.

"So many people with basements have a false sense of security because they have only a beam ceiling," he said. "If the house blows away, now you have a basement open to the sky. We have found a lot of basements filled with debris and even automobiles."

That brings us back to those notorious mobile home parks that seem to be a target of tornadoes. Some states are now requiring mobile home parks to have a storm shelter of some sort.

Unfortunately, human nature is such a contrary thing. Even when such a safe place is available, not everyone uses it in times of storms.

Reinhold tells me this tale: In the recent tornadoes that hit Birmingham, Ala., a community on the north side of the city boasted 110 homes with tornado shelters. Although the storm slid past the community, a powerful tornado did appear imminent, yet only two families used their shelters.

"Either they didn't perceive there was a risk or they didn't know about the storm approaching," Reinhold said.